I set a background image (arrow down) to a select box after setting the webkit-appearance attribute to none. When the option list is opened I want to display another background image (arrow up). Is there a pseudo class or something for it? I couldn't find anything during my research...
It's not possible to detect if a HTML select element is opened using CSS, or even javascript.
If you wish to customise the arrow symbol of a custom dropdown, your best option is to use a custom dropdown component which maps to a hidden select element.